Additionally you need to decide if the hassle of accepting ‘offline’ or non-credit card payments is worth it for your business. Some companies just cannot purchase any other way but it will involve extra hassle for you (paperwork, chasing payments, waiting 30, 60 90 days etc) so do your prices allow for that?

You are already using FastSpring. You can prepare and invoice for a customer in the backend of FastSpring and just send them a link or copy of the pdf invoice (just search their knowledge base on how to do that).

I’ve found Order Creator in my Fastspring account. It lets me select my product, asks minimal customer info (company name, contact name and email) and generates a web page invoice. I can then send this link to the prospective customer and she can review the invoice, provide more details and make the payment.

Almost exactly what I was looking for! I hope a customer will find it satisfying as well. Thanks for the help unboot!